Step 10: Finish the Nose Cone

Step 11: Attach Nose Cone to Body

Finally, turn the nose cone over and fill it 3/4 of the way full with hot glue. Be careful here, so that you don't burn yourself. The paper will get w...

Step 7: Making The Fins

Now, carefully, take one piece of tape and fold it over on itself, leaving about 1/4in "tabs" of tape at the end. Then, using your scissors, make a 45 degree cut to create the triangular shape of the fin. Repeat this with the other two pieces of tape, for a total of 3 tail fins.

You just fold the tape over so that it sticks to itself, only leave a little bit at the end that isn't stuck together, and use that part to attach it to the rocket body. Then take scissors and trim the "flap" you just made so that it's triagular.

I think I understand. We've to just fold it to half carefully, just like we do on paper to cut it in to equal parts. Here the folding is done such that small part of end are free and then we cut it as you said.